DE10016714A1 - Device for emitting radiation e.g. for lighting up numbers, lettering and symbols, uses light conductors, LEDs and radiation emitting encased diodes mounted on a printed circuit board - Google Patents

Abstract

The diodes are mounted on a printed circuit board and a fiber-optic light guide (1) is positioned on the structure of this printed circuit board. Two-pole diodes are used in a MELF casing and molded in between the front and rear sides of the fiber-optic light guide. One pole (3) of the radiation emitter can be seen on the front side of a radiation waveguide and the other (4) seen on the rear side of the radiation waveguide.

Description

The invention relates to a radiation-emitting device consisting of a radiation conductor with a front and a back and radiation-emitting, bipolar semiconductor components.

The LED lamps currently available on the market are in the form of contacted leadframes in plastic housings, where the Connections for mounting the two-pole element arranged on one level are.

The chip-encapsulating plastic housing together with the strip in the essential as an optical system, the emission characteristics of the light emitting diode. Due to the special plastic material, the component is given a large size Resistance to mechanical influences and moisture.

For illuminating large areas such as display boards, information signs, and The individual components are illuminated electrically as rows or Parallel connection interconnected several times.

Also LEDs that are either in a housing or simply mounted as a chip on a printed circuit board, inserted in light guides. These structures are used primarily for the uniform illumination of larger ones Surfaces, in particular as backlighting for LCD displays. Here the light emitting diodes and the light guides are always constructed in such a way that above all that Light that emerges on the top of the light-emitting diode allows lossless in the Optical fiber is coupled. For this, the light emitting diode is used with different provided complex optics.  

A disadvantage of these structures, however, is the complex assembly, since the Components must be positioned exactly together with the optics. Furthermore are the costs due to the additional optics required high and the dimensions such lighting arrangements too large for many applications. However, will dispenses with the complex additional optics, so is the illumination of the Buildings uneven.

DE 197 51 911 A1 describes a light-emitting diode in a MELF housing disclosed. Here is the light emitting diode, clamped between two Metal stamps, in a glass tube, the two metal stamps the Close both ends of the glass tube.

In the conference article from 11th Capacitor and Resistor Technology Symposium, CARTS '91, Huntsville, AL, USA: Components Technol. Inst. 1991 ,. p. 38-41; Krumbiegel, A. and others: 'Insert mounting - the breakthrough into the third dimension 'an arrangement is shown in which two-pole Resistors and silicon diodes in a MELF housing for reasons of space in one PCB are mounted. Here, the circuit board has holes between Front and back into which the MELF components are inserted so that One pole of the component is arranged on the front and rear of the circuit board is.

The object of the invention is a radiation emitting over a large area Show device that is simple and low in height inexpensive construction allowed.

The object is achieved by the features in the characterizing part of patent claim 1. Here, semiconductor components ( 2 ) are arranged in a form-locking manner in a radiation conductor between its front and rear sides, one pole ( 3 , 4 ) of the semiconductor component ( 2 ) in the region of the front side and another pole ( 4 , 3 ) in the region of the rear side of the Light guide ( 1 ) is arranged.

Advantageous developments of the invention result from the dependent Claims. Here, radiation-emitting components are preferably used in the MELF Housing used. The structure of such a device can be so  that either holes are drilled in the radiation conductor are then equipped with the radiation-emitting components be, or the housed components are used in the manufacture of the Potted light guide. The light guide is also used in such structures Places where the light emission is undesirable with reflective Devices and where the light under a certain angle and with a certain brightness, the Surface structure of the light guide during the manufacture with the for this required optics. The light guide can also be flexible so that it can be given shapes. Furthermore, through a simple Surface metallization of conductor tracks or reflective coatings the radiation-emitting device can be applied.

The advantages of the invention are that a large area radiation-emitting device easily assembled and inexpensive can be manufactured and built. The components are made by the Positioned positively and can, since your connections directly to the Conductor tracks are, be soldered. Another advantage is that the entire structure due to the hermetically sealed MELF housing low degradation and insensitive to the effects of moisture. By the flexible structure and low height is adaptable to given any shape.

The invention is intended to be described in the following with the aid of exemplary embodiments and figures are explained in more detail. Brief description of the figures:

Fig. 1 cross section through the radiation-emitting device.

Fig. 2 front of the radiation-emitting device.

Fig. 3 back of the radiation-emitting device.

Fig. 4A-E method for building a radiation-emitting device.

FIG. 4A manufacture of the light guide.

Fig. 4B application of the conductor tracks on the light guide.

Fig. 4C making the holes in the light guide.

Fig. 4D insertion of the MELF LEDs in the light guide.

Fig. 4E contacting the MELF LEDs.

Fig. 1 shows the cross section through the radiation-emitting device. The light guide 1 has through bores or holes 16 . These holes 16 run continuously from the upper front side, at which the light is to exit, to the lower rear side. The light-emitting diodes 2 are located in the holes 16 and are arranged in a hermetically sealed MELF housing. It is characteristic of the MELF housing that the radiation-emitting chip 5 is clamped between two metallic stamps and is located in a glass housing 12 , which in addition to the cost-effective production also results in a low overall height, a hermetically sealed housing and an arrangement of the which is favorable for this application results in two poles 3 , 4 , which form a straight extension of the chip contact surfaces. In this application example, the thickness of the light guide of approx. D = 2 mm corresponds to the overall height of the MicroMELF diodes. The diameter of the holes with ∅ = 1.2 mm also corresponds to the diameter of the Micro-MELF diodes. The light guide 1 consists of plexiglass or polymethyl methacrylate (PMMA). This material can be produced in any form in the sink-molding process. So you can make the production of complex shaped surfaces such. B. grooves, notches, Fresnel lenses. Blank pressing and injection molding make it easy to obtain components with aspherical surfaces, the accuracy of which is sufficient for lighting and simple imaging systems. In the application example, the light guide 1 is provided on the underside with reflection notches 6 , which are mirrored due to a higher light yield, in that a metallization 7 is applied to the underside of the device. The reflection notches 6 serve to decouple the radiation 15 at a desired point. Due to the small thickness d of the light guide 1 , it can be configured flexibly, so that it can be bent into the desired shape. The conductor tracks 18 , 19 , which are also applied in the case of metallization, are likewise located on the front and back. In order to connect the top pole 3 and the bottom pole 4 of the light-emitting diode in the light guide 1 to the conductor tracks, one pole is soldered to a conductor track. This simultaneously creates covers 10 , 11 from the solder material. These covers 10 , 11 serve both to make an electrical contact and also to prevent the LED 2 from sliding out of the light guide 1 . To reduce the losses on the side, the light guide is also provided with an end face metallization 8 and thus mirrored. The light guide can also contain pigments 13 which scatter the light in the desired direction or convert short-wave radiation into long-wave radiation.

Fig. 2 shows the front side of the radiation-emitting device. In this application example, the radiation or light is coupled out at the top. Textures 17 are applied to the surface of the front side of the light guide 1 , for example by roughening the surface at this point or by forming other structures there which enable light to be coupled out at these points. These textures 17 can represent letters, numbers, symbols or areas to be illuminated. Around the textures 17 there are soldering points 10 of the MELF diodes 2 with the radiation-emitting semiconductor element 5 inserted into the light guide 1 . The light guide itself contains pigments 13 with which the radiation is scattered in the light guide or the color of the light can also be changed. The structure, as shown here, can also include reflector troughs of any design, which deflect the light to the desired location or have no reflector structures at all inside the radiation conductor 1 . Furthermore, interconnects 18 are attached on the upper side in order to connect a pole of the light-emitting diodes to an electrical energy source. The poles of different LEDs can also be connected to one another with the conductor tracks 18 , as shown in the application example. In a further exemplary embodiment, not shown, the upper side can also be metallized or mirrored or covered with a reflector layer. However, this should only be done where the light emission is undesirable.

In contrast, Fig. 3 shows the back of the radiation emitting device. Conductor tracks 19 are also arranged here. However, the underside with the reflectors projecting inwards was almost completely covered with a reflective metallization 7 . Only small areas are left out in order to delimit the metallization 7 from the conductor tracks 19 . The MELF LEDs 2 are inserted at the locations where the holes are in the light guide 1 . Each MELF light-emitting diode 2 is surrounded by a honeycomb-shaped reflector arrangement which distributes the light that is generated in the semiconductor component 5 evenly. The MELF LEDs 2 are electrically connected to the conductor tracks 19 by soldering points 11 on the underside. They also serve as a cover 11 of the MELF light-emitting diode 2 in order to close the holes in the light guide 1 .

A method for constructing a radiation-emitting device is shown in the next FIGS. 4A-E.

Fig. 4A shows the optical fibers 1. This consists, for example, of plexiglass or polymethyl methacrylate (PMMA), which has very good properties with regard to light conduction, decoupling and color stability. This material can be produced in any form in the sink-molding process. As a result, complicatedly shaped surfaces such as grooves, notches and Fresnel lenses can be easily integrated in the manufacture of the light guide. Blank pressing and injection molding make it easy to obtain components with aspherical surfaces, the accuracy of which is sufficient for lighting and simple imaging systems. Since the micro-MELF LED has a length of approximately 1.9 mm and a diameter of 1.2 mm, a 2 mm thick PMMA plate 1 will be used, the honeycomb-shaped reflection troughs 6 arranged on the underside on the underside or also simply Has reflection notches. These serve to redirect the radiation to the desired location. Textures 17 are attached to the top, that is to say areas where the light is to be coupled out. These textures 17 can represent letters, numbers, symbols or areas. The thickness of the light guide 1 of approximately 2 mm also allows a flexible design in order to adapt it to housing shapes or other dimensional requirements.

FIG. 4B shows the front surface of the light conductor 1 with the conductive tracks 18. After applying a full-surface metallization with a reflective metal, a spray coating is applied to structure the conductor tracks 18 and to reinforce the reflection areas in the photoresist technology.

This is followed by the galvanic amplification of the photolithographically exposed conductor tracks and reflection areas. Then the two areas are galvanically separated by briefly etching the metallization. In the figure, only the front side with the textures 17 and the conductor tracks 18 is visible, the metallized reflection areas, the honeycomb-shaped reflectors 6 and further conductor tracks are on the rear side. After the formation of the conductor tracks 18 and the reflective metal layer, the bores are made in the light guide, as shown in FIG. 4C.

FIG. 4C shows the structured, metallized light guide 1 which forms conductor tracks 18 and has holes 16 in the conductor track structure at several locations. The diameter of the holes 16 should correspond to that of the MELF LEDs, so that a fit that is as precise as possible is created in order to avoid loss of light when changing into different media and slipping of the components. The holes 16 extend from the front to the back. Furthermore, the holes are arranged in such a way that they are located in a honeycomb-shaped reflector 6 which distributes the radiation emerging laterally from the MELF housing. There are no holes 16 in a texture 17 .

In Fig. 4D, the MELF LEDs 2 are introduced into the holes 16 along the conductor paths 18. The MELF diodes 2 are inserted into the light guide 1 in the longitudinal direction in such a way that they each have a contact on the front and back and are arranged in the honeycomb reflectors 6 around the textures 17 .

In FIG. 4E, the MELF LEDs are soldered into the light guide 1 along the conductor tracks 18 in such a way that one pole on the front and the other pole on the rear of the light guide is connected to the conductor tracks 18 . The solder points 10 shown also form the closure, which prevents the MELF diodes 2 from falling out. A portion of the underside of the arrangement shown in this figure is already shown in FIG. 3.

Another manufacturing process, not shown, can proceed in such a way that that the MELF diodes are cast at the same time when the radiation conductor is cast become. The metallization can then be applied as a reflector layer and be structured for the production of the conductor tracks.  

Depending on the structure, radiation-emitting devices constructed in this way can of the radiation semiconductor can be used for various purposes. Depending on The presence or structure of the reflectors in the radiation guide can be a areal illumination, for example for backlighting LCD displays, generated or letters, characters, numbers can be illuminated become. It can also be used to generate matrix-like structures that For example, to illuminate a third brake light in the high position Motor vehicle could be used. Even with such Device matrix points can be controlled individually and thus z. B. Tickers can be realized.

Also, with such a structure, it is not imperative that the light is decoupled at the front, but the other sides, in particular the face can also be used for this.

Claims (10)

1. Radiation-emitting device, consisting of a flat radiation conductor ( 1 ) with a front side which has at least one radiation exit surface ( 17 ), and a rear side and radiation-emitting semiconductor components ( 2 ) in a two-pole housing, characterized in that

• - Semiconductor components ( 2 ) are arranged in a form-fitting manner in the radiation conductor ( 1 ) between the front and the back and thereby
• - The one pole ( 3 , 4 ) of the semiconductor component ( 2 ) is arranged in the region of the front and another pole ( 4 , 3 ) in the region of the rear of the light guide ( 1 ).

2. Radiation-emitting device according to claim 1, characterized in that the semiconductor component ( 2 ) has a MELF, mini or micro-MELF housing. 3. A method for producing a radiation-emitting device according to claim 1 or 2, characterized in that first holes ( 16 ) are made in the radiation conductor ( 1 ) between the front and the back, the dimensions of the holes ( 16 ) being those of the semiconductor components ( 2 ) correspond and then the bores ( 16 ) are equipped with the semiconductor components ( 2 ). 4. A method for producing a radiation-emitting device according to claim 1 or 2, wherein the radiation conductor ( 1 ) is made from a sealing compound, characterized in that the semiconductor components ( 2 ) are cast in during the manufacture of the radiation conductor ( 1 ). 5. Radiation-emitting device according to claim 1, wherein the radiation conductor ( 1 ) has end faces between the front and back, characterized in that the end faces of the radiation conductor ( 1 ) are provided with a reflection layer ( 8 ) or the surface of the end face reflectors ( 6 ) train. 6. radiation-emitting device according to claim 1, characterized in that the front and back of the equipped with the semiconductor devices (2) radiation conductor (1) conductor tracks (18, 19) for energizing the semiconductor components (2). 7. Radiation-emitting device according to claim 1, characterized in that the back is at least partially provided with a reflection layer ( 7 ) or the surface of the back forms reflectors ( 6 ). 8. Radiation-emitting device according to claims 4 and 5, characterized in that the reflection layer ( 7 , 9 ) forms conductor tracks ( 18 , 19 ). 9. Radiation-emitting device according to claim 1, characterized in that the front of the radiation conductor has surface structures ( 17 ) for coupling out radiation. 10. Radiation-emitting device according to claim 1, characterized in that the perforated radiation conductor ( 1 ) with the integrated radiation-emitting semiconductor components ( 2 ) is flexible.